"Microsoft 365 Business is the coming together of all of these products in a very compelling offer and package for every small business, every medium-sized business to have the same tools, the same sophistication that any large business has," Nadella said during his Inspire keynote.

An enterprise version, Microsoft 365 Enterprise, is an evolution of Secure Productive Enterprise, which was already available in E3 and E5 SKUs, and is supposed to be generally available (GA) this quarter.

As a completely new bundle, Microsoft 365 Business is only entering the public preview stage on Wednesday. Microsoft currently says a fully supported version will be available by the end of the year.

For now, the preview is free, although Microsoft recommends that customers hire a partner to deploy the solution. At GA, Microsoft 365 Business will cost $20 per user, compared to the $12.50 per user charge for Office 365 Business Premium. Like Office 365 Business Premium, Microsoft 365 Business includes Microsoft Office, 1TB of file storage, a 50GB mailbox, online meetings, Microsoft Teams, and business applications including Outlook Customer Manager, Bookings and MileIQ.

The $7.50/user/month premium for the release version of Microsoft 365 Business will get organizations Windows 10 Pro upgrade rights for users with Windows 7 or Windows 8.1, as well as Windows Defender and other security features and device management features, such as a single console to manage user and device settings, self-service PC deployment, and automatic deployment of Office apps to Windows 10 PCs.

Organizations that are currently paying for Office 365 will need to continue to pay the subscription while using the public preview, Microsoft said in a FAQ.

Microsoft 365 Business is meant for organizations with no full-time IT staff, no Active Directory domain controllers and fewer than 300 users. The FAQ states that customers using on-premises Active Directory "must switch to cloud identity and management as part of their deployment."